RÉSUMÉ La Spectroscopie de Décharge Luminescente (SDL) à détection optique est une technique rapide et fi able pour l'analyse élémentaire des solides. Le potentiel de la SDL à détection optique comme technique de spéciation du solide...
moreRÉSUMÉ La Spectroscopie de Décharge Luminescente (SDL) à détection optique est une technique rapide et fi able pour l'analyse élémentaire des solides. Le potentiel de la SDL à détection optique comme technique de spéciation du solide a été évalué dans le contexte de la mise en place de nouvelles législations européennes (RoHS ou directive 2000/53 sur les véhicules en fi n de vie) mettant en avant la dangerosité de certaines espèces chimiques. Les informations de spéciation accessibles en SDL étant dépendantes de la détermination de la concentration en oxygène, une amélioration du processus de détection et de quantifi cation de la SDL pour les éléments légers a été entreprise. Des résultats illustrant le potentiel ainsi que les limitations de la méthode sont présentés dans cet article. MOTS-CLÉS Méthodologie analytique, SDL, spéciation, analyse des éléments légers The Glow Discharge Optical Emission Spectroscopy as a speciation technique : potential and limitations SUMMARY Glow D...
ABSTRACT Hydrogenated silicon-carbon thin films were deposited by Radio Frequency Plasma Enhanced Chemical Vapor Deposition using silane-methane gas mixtures highly diluted in hydrogen. The effects of the presence of a microcrystalline...
moreABSTRACT Hydrogenated silicon-carbon thin films were deposited by Radio Frequency Plasma Enhanced Chemical Vapor Deposition using silane-methane gas mixtures highly diluted in hydrogen. The effects of the presence of a microcrystalline silicon seed layer and of the methane flow rate during deposition were investigated in order to find the optimal conditions for microcrystalline growth. The presence of a seed layer promotes the amorphous to microcrystalline transition at the interface with the substrate, reducing the incubation layer to a 5-10 nm thickness. At the same time, an excessive increase in the CH4 flow rate suppresses crystalline growth, leading to extremely flat amorphous samples (root-mean-square surface roughness ρRMS ∼ 0.5 nm), even with a seed layer. The total carbon content was measured by Radio Frequency Glow Discharge Optical Emission Spectroscopy. It was found that carbon is only incorporated in the amorphous tissue, and not in the crystalline phase. Thus, the increase of the crystalline fraction, directly linked to the increase of the seed layer deposition time, leads to a decrease of the carbon incorporation in the subsequent layer.
ABSTRACT The performance of a newly developed pulsed RF glow discharge time-of-flight mass spectrometer (GD TOFMS) in analysis of elemental distributions of impurity species, particularly Cr, B, P, Cl and Cu in anodic film on aluminium...
moreABSTRACT The performance of a newly developed pulsed RF glow discharge time-of-flight mass spectrometer (GD TOFMS) in analysis of elemental distributions of impurity species, particularly Cr, B, P, Cl and Cu in anodic film on aluminium and beneath the anodic alumina/aluminium interface and P, B, Cr and H in anodic film on tantalum and beneath the anodic tantala/tantalum interface, with high resolution is presented. The orthogonal TOFMS combined with an appropriate acquisition system enables monitoring of ion signals within the glow discharge period, i.e. during the RF pulse, and within following afterglow, where signals of high intensity, resulting from Penning ionisation, are observed. It was found that GD TOFMS profiling is an extremely powerful and reliable technique for depth profiling analysis that is confirmed from the depth distribution of impurities in the thin, non-conducting, anodic oxide films. The developed configuration allows analysis of layers as thin as 2 nm thickness that are enriched with both positive and negative ions.
ABSTRACT Experiments on solid-phase electrosurface migration through formally inert eutectic WO3|MeWO4 interfaces in symmetric electrochemical cells such as Pt|WO3|MeWO4|WO3|Pt are performed. It is shown that the most significant changes...
moreABSTRACT Experiments on solid-phase electrosurface migration through formally inert eutectic WO3|MeWO4 interfaces in symmetric electrochemical cells such as Pt|WO3|MeWO4|WO3|Pt are performed. It is shown that the most significant changes occur at the “cathode” interface (−)Pt|WO3|MeWO4|, where counter electrosurface drawing of WO3 to the inner surface of MeWO4 ceramics (with the formation of two-phase distributed composite WO3|MeWO4) and a much smaller flow of Me2+ components to the WO3 ceramics depth are observed. Scanning and transmission electron microscopy showed the formation of nano- and microscale objects of various shape in grain boundaries’ regions, among which well-faceted nanoobjects shaped as ribbons and rods from a few to hundreds of nanometers thick are noticeable. The Ca and Sr contents in WO 3(−) cathode pellets after experiments in cells are determined by X-ray fluorescence analysis, scanning electron microscopy, energy-dispersive analysis, and depth profiling using glow-discharge spectrometry. The data obtained are interpreted based on the concepts of solid-phase electrocapillarity (WO3 migration) and electrochemical intercalation of Me into the WO3 structure.
ABSTRACT A comparison is made between plasma profiling time‐of‐flight mass spectrometry (PP‐TOFMS) and nuclear reaction analysis (NRA) for depth profiling of 18O tracer in porous anodic oxide films on aluminum. The films were formed...
moreABSTRACT A comparison is made between plasma profiling time‐of‐flight mass spectrometry (PP‐TOFMS) and nuclear reaction analysis (NRA) for depth profiling of 18O tracer in porous anodic oxide films on aluminum. The films were formed galvanostatically, for a range of times, using phosphoric acid electrolytes that were either enriched in 18O or of the natural isotopic concentration. The morphologies of the films were determined by electron microscopy. The findings from PP‐TOFMS and NRA reveal a partitioning of the tracer between the surface regions and buried layers of the films. However, a relatively high background of 16O in PP‐TOFMS prevents a reliable quantification of the concentration of 18O. Copyright © 2012 John Wiley & Sons, Ltd.
ABSTRACT The performance of glow discharge time-of-flight mass spectrometry in isotopic differentiation is revealed using the distribution of oxygen isotopes 16O and 18O in barrier-type anodic alumina films as a focus. Anodic alumina...
moreABSTRACT The performance of glow discharge time-of-flight mass spectrometry in isotopic differentiation is revealed using the distribution of oxygen isotopes 16O and 18O in barrier-type anodic alumina films as a focus. Anodic alumina films comprising 18O-rich layers of controlled thickness were formed by the appropriate combination of anodising of superpure aluminium in electrolytes enriched with 18O isotopes and of natural abundance of 18O isotopes. Analysis of the elemental depth profiles of selected ionic species, i.e. 16O18O, allowed determination of the locations of the 18O-rich layers and the 18O/16O interface. Copyright © 2010 John Wiley & Sons, Ltd.
ABSTRACT Glow discharge optical emission spectroscopy (GD-OES) has been shown to be of immense value in elemental depth profiling of thin or thick films on conductive or non-conductive substrates. For aluminium, GD-OES has been employed...
moreABSTRACT Glow discharge optical emission spectroscopy (GD-OES) has been shown to be of immense value in elemental depth profiling of thin or thick films on conductive or non-conductive substrates. For aluminium, GD-OES has been employed to examine locations of markers and tracers in anodic films, thereby assisting understanding of transport phenomena. In order to investigate the influence of surface topography on depth profiling analysis, anodic aluminium oxide films of various thicknesses, with incorporated electrolyte species, were produced on superpure aluminium substrates of controlled roughnesses. The distributions of incorporated species in the films were subsequently probed. Surface topography modifications and consequent depth resolution degradation were examined during depth profiling analysis performed by GD-OES. The results reveal that the sputtering process leads to the roughening or smoothing of the surface topography of the specimen for a ratio of the film thickness to the amplitude of the substrate texture less, or greater, than 1 respectively. As a consequence of the surface topography dependence of the ion bombardment, analysis of thin films over rough surfaces suffers from depth resolution limitations due to sputtering-induced topography changes, thereby limiting quantification of the resultant spectra. Copyright © 2010 John Wiley & Sons, Ltd.
ABSTRACT Glow discharge mass spectrometry has been widely used for trace and ultra-trace element analysis of high-purity alloys. A novel pulsed radio frequency glow discharge time-of-flight mass spectrometer (rf GD TOFMS) has been...
moreABSTRACT Glow discharge mass spectrometry has been widely used for trace and ultra-trace element analysis of high-purity alloys. A novel pulsed radio frequency glow discharge time-of-flight mass spectrometer (rf GD TOFMS) has been developed that retains the pulsed radio frequency analytical ion source to provide ion signal enhancement due to processes involving Penning ionisation. A time-resolved detection mode has been implemented to sample the afterglow regime of the pulse profile, corresponding to the highest ion signal intensities. Here, the performance of rf GD TOFMS in isotope differentiation is discussed. Anodic tantala films, comprising 18O-rich layers of controlled thicknesses and locations, were formed by appropriate combination of anodising of tantalum in electrolytes enriched with 18O isotopes and of natural O isotopic abundance. Transmission electron microscopy (TEM) and radio frequency glow discharge optical emission spectrometry (rf GD OES) analyses were performed to examine the morphology and elemental distributions of the specimens, while the content of 18O in the 18O-rich layers was determined by elastic recoil detection analysis(ERDA). In pulsed rf GD TOFMS analysis, characteristic ionic species formed in the glow discharge allows differentiation of 18O-rich layers. Particularly, the location of 18O-rich layers was determined from the 16O18O and Ta18O ion signals at masses m/z 34 and 199, respectively. The locations of 18O-rich layers in anodic films, controlled by the selected anodising conditions, were probed precisely. The 18O profiles in anodic tantala were directly compared with those obtained by dual beam time-of-flight SIMS. Copyright © 2009 John Wiley & Sons, Ltd.
ABSTRACT A detailed theory of relative sputtering rates for glow discharge optical emission spectroscopy (GDOES) is presented for the first time. The theory suggests that such sputtering rates should be nearly independent of plasma...
moreABSTRACT A detailed theory of relative sputtering rates for glow discharge optical emission spectroscopy (GDOES) is presented for the first time. The theory suggests that such sputtering rates should be nearly independent of plasma conditions. This is supported by experimental results for r.f. GDOES under varying applied power or varying pressure. Relative sputtering rates are calculated for a range of cast irons, high-alloy steels and zinc–aluminium alloys. Within measurement uncertainties, the calculated rates agree with measured relative sputtering rates. Copyright © 2003 John Wiley & Sons, Ltd.
ABSTRACT The depth resolutions achieved by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and glow discharge optical emission spectroscopy (GD-OES) are comparable for the analysis of relatively flat specimens. However, the...
moreABSTRACT The depth resolutions achieved by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and glow discharge optical emission spectroscopy (GD-OES) are comparable for the analysis of relatively flat specimens. However, the precision of sputtering-induced depth profiling techniques has been shown to be dramatically influenced by the initial roughness of specimen surface. The effect of the specimen roughness on the depth resolution achieved by both techniques has been examined here using textured aluminium substrates supporting anodic oxide films. As a result of dissimilarities in the sputtering processes, TOF-SIMS and GD-OES show significantly different elemental depth profiles for electrolyte-derived species incorporated into anodic oxide films formed on superpure aluminium substrates of controlled texture. Copyright (C) 2010 John Wiley & Sons, Ltd.
ABSTRACT This paper reports experimental results for near-surface Ti sputter target oxidation in a magnetron racetrack during reactive high power impulse magnetron sputtering (HIPIMS) at various optical plasma monitoring set-points in the...
moreABSTRACT This paper reports experimental results for near-surface Ti sputter target oxidation in a magnetron racetrack during reactive high power impulse magnetron sputtering (HIPIMS) at various optical plasma monitoring set-points in the transition region between 'metal' and 'poisoned' target states. Oxygen depth profiles were obtained by nuclear reaction analysis and glow discharge optical emission spectroscopy. Ti target surface oxidation depth as induced by reactive HIPIMS was found to depend on the process set-point as well as discharge conditions. Deepest oxidation was observed when operating close to 'fully poisoned (FP)' or in 'FP' regime with oxygen profiles extending as deep as ~0.5 µm (oxygen concentration ≥5 at%). Oxygen profiles obtained indicate the occurrence of oxygen bulk diffusion. Process induced elevated target surface temperature, magnetic field and plasma assistance are suggested to contribute substantially to these profiles. Based on these findings it is proposed that ion-bombardment-assisted thermal diffusion is a third target poisoning mechanism that can be taking place and is therefore important in reactive HIPIMS in addition to the two currently accepted mechanisms—ion implantation and chemisorption. Under the conditions investigated in this work, diffusive oxidation was most significant when operating in the lower part of the hysteresis loop. Reactive HIPIMS processes that will facilitate significant diffusive sputter target surface oxidation will also be expected to exhibit wider hysteresis and longer target cleaning times after substantial target poisoning.
ABSTRACT Static and dynamic magnetic properties of composition-graded FeCoTa thin films were systematically studied with respect to temperature and the deposition power of Ta target. The magnetic anisotropy field and ferromagnetic...
moreABSTRACT Static and dynamic magnetic properties of composition-graded FeCoTa thin films were systematically studied with respect to temperature and the deposition power of Ta target. The magnetic anisotropy field and ferromagnetic resonance frequency were found to be increased with the increasing of deposition power of Ta target due to the enhancement of stress when Ta concentration is increased. Thermal stability of the films shows a very interesting behavior with a peculiar and large increasing of magnetic anisotropy with temperature when the deposition power for Ta is moderate while it exhibits normal decreasing with temperature when the deposition power is low or high. The results are discussed and explained in terms of the magneto-elastic anisotropy contribution when the stress of the films is varied.
ABSTRACT A calibration procedure for content depth profile analysis by glow discharge optical emission spectroscopy is presented. This new method is based on the well established relative or internal standard method. The method allows...
moreABSTRACT A calibration procedure for content depth profile analysis by glow discharge optical emission spectroscopy is presented. This new method is based on the well established relative or internal standard method. The method allows reduction of the number of CRM with known sputtering rates to a strict minimum, while still using a large number of CRMs for establishing the analytical curves. The new calibration method allows the uncertainty in the calculation of the chemical composition to be separated from the uncertainties of sputtering rate measurements. The application of this new calibration procedure is applied to industrial samples and further possible improvements are discussed.
ABSTRACT Radiofrequency glow discharge (rf-GD) coupled to optical emission spectrometry (OES) provides depth-resolved elemental composition information on a wide variety of sample types. However, quantitative studies in protective coating...
moreABSTRACT Radiofrequency glow discharge (rf-GD) coupled to optical emission spectrometry (OES) provides depth-resolved elemental composition information on a wide variety of sample types. However, quantitative studies in protective coating materials (e.g. oxides, nitrides, etc.) are severely limited by the lack of certified standards containing known amounts of oxygen and nitrogen. The potential of rf-GD-OES for quantification of oxide films has been investigated in this work using an alternative quantification methodology with correction for dc bias voltage. Oxygen calibration curves were obtained by combining two types of standards; bulk certified reference materials and well-characterised coated calibration samples. Three oxide films, including anodic alumina and iron oxide films were studied at 700 Pa of pressure and 30 W of forward power. The qualitative and quantitative in-depth profiles proved satisfactory results for depths and concentrations, in agreement with nominal values. In addition, in order to evaluate the possibilities of solid-state speciation with rf-GD-OES, the metal to oxygen ratios (Al/O for the anodic alumina film and Fe/O for the iron oxide films) in the quantitative depth profiles were investigated. Preliminary results for the oxidation states of aluminium and iron were properly compared with X-ray diffraction (XRD) measurements, demonstrating the excellent capabilities of the GD-OES technique. Further possible improvements are discussed and it is believed that the proposed speciation strategy holds a great deal of promise in the solid-state speciation area.
The analytical potential of a radiofrequency glow discharge orthogonal time-of-flight mass spectrometer (RFGD-TOFMS) has been evaluated in both pulsed and non-pulsed modes. A certified reference steel was selected for this study. The...
moreThe analytical potential of a radiofrequency glow discharge orthogonal time-of-flight mass spectrometer (RFGD-TOFMS) has been evaluated in both pulsed and non-pulsed modes. A certified reference steel was selected for this study. The operating conditions of the GD ...
ABSTRACT Aiming at minimizing microleaks in the seal between the sample and the GD, a surrounding chamber which warrants a continuous isolating argon flow around the solid sample during the analysis, has been investigated for...
moreABSTRACT Aiming at minimizing microleaks in the seal between the sample and the GD, a surrounding chamber which warrants a continuous isolating argon flow around the solid sample during the analysis, has been investigated for radiofrequency (rf) glow discharge (GD) coupled to time of flightmass spectrometry (TOFMS) applications. Three standard reference materials and two thin coatings were analysed comparing the influence of the purging pre-chamber in the analytical results, both in non-pulsed and pulsed rf-GD operation modes. Results show that the external argon flow seems to reduce the microleaks between the sample and the GD source since a diminished level of polyatomics appeared in the recorded mass spectra. Additionally, using the rf non-pulsed mode better signal reproducibility, less polyatomic interferences and, in some cases, higher ion signals could be achieved. In terms of in-depth profile capabilities, a faster penetration rate was observed when the pre-chamber was used and such difference was dependent on the sample composition. Comparatively, less benefit was apparent using the rf-pulsed mode as the temporal discrimination in such mode allows to separate analytical ion signals from interfering contaminants.
ABSTRACT The radio frequency (RF) powered source is the most stable and capable analytical source available for glow discharge optical emission spectroscopy (GD-OES). It allows the direct analysis of both conductive and non-conductive...
moreABSTRACT The radio frequency (RF) powered source is the most stable and capable analytical source available for glow discharge optical emission spectroscopy (GD-OES). It allows the direct analysis of both conductive and non-conductive samples on the same source, without changing the source. Recent developments in RF generators and components have further improved the performance of these sources, and now allow the routine measurement of additional RF parameters such as applied voltage and DC bias voltage. Theoretical studies of the fundamental characteristics of the RF source are providing deeper understanding of how they work, and combined with the new measurement tools will lead to further improvements in analytical performance. Recent theoretical and experimental work on the RF plasma source will be presented. These studies will be illustrated with some recent applications: in metals analysis, plus a hard coating and a non-conductive coating.
ABSTRACT Existing silicon oxynitride (SiON) dielectric can only provide a very near term solution for the metal oxide semiconductor technology. The emerging high-k dielectric materials have a limited thermal stability and are prone to...
moreABSTRACT Existing silicon oxynitride (SiON) dielectric can only provide a very near term solution for the metal oxide semiconductor technology. The emerging high-k dielectric materials have a limited thermal stability and are prone to electrical behavior degradation which is associated with unwanted chemical reactions with silicon (Si). We investigated here applicability of amorphous boron oxynitride (BON) thin films as an emerging dielectric for high temperature capacitors. BON samples of thickness varying from 200 nm down to 10 nm were deposited in a high vacuum reactor using ion source assisted physical vapor deposition (PVD) technique. Plasma profiling ion mass spectrometry (P2IMS) was utilized to specifically determine the interface quality and best capacitor performance as a function of growth temperatures of a graded sample with alternate layers of deposited titanium (Ti) and BON layers on Si. P2IMS depth profiling of these layers were also performed to evaluate the stability of the dielectric layers and their efficacy against B dopant diffusion simulating processes occurring in activated polySi-based devices. For this purpose, BON layers were deposited on boron-isotope 10 (B10) implanted Si substrates and subsequently annealed at high temperatures up to 1050 °C for about 10 s. Results comparing inter-diffusion of B10 intensities at the interfaces of BON–Si and SiON–Si samples suggest suitability of BON as barrier layers against boron diffusion at high temperature. Stable Ti/BON/Ti capacitor behavior was achieved at optimum growth temperature of 600 °C of the BON dielectric layer. Capacitance change with frequency (10 kHz to 2 MHz) and temperature up to 400 °C is about 1% and 10%, respectively.